Unable to click mobile menu in iPhone 5 Safari

Hi Support, Hopefully this will be my last issue for a while... :( Did a random test of visiting my site tuanzbuild.tuanz.org.nz on both my iPpone 5 and 5s and iPad mini. iPhone 5 and 5s mobile menu does not work when viewing in portrait, but in landscape works fine for some reason. Have cleared cache and browsing data, issue still persists. Mobile menu on iPad mini works fine on both orientations. 1 mutual problem with my FB app widget and the Twitter follow button is that it moves it self to the left a bit on the home page as you can see here: https://www.dropbox.com/s/fsql4bcxytet0x5/Photo%20Apr%2025%2C%2011%2004%2039%20PM.png?dl=0 (this is only on landscape orientation on both my iPhones 5 and 5s and my iPad mini) Any suggested css code that could help this? Thanks, Rob